Patent GB-736919-A (GB)
Title: Preservation of microbial spores or cells
IPC: C12N1/04
Filed: 1953-06-19
Abstract: An animal food supplement consists of a food supplement such as skim milk or vitamins and viable spores or cells of fungi including the subdivision Schizomycetes, and especially the bacterial flora from rumen juice, preserved by mixing a moist but not liquid host medium containing the spores or cells, with a sterile water-soluble non-toxic crystalline carrier in granule form so that the spores or cells adhere to the surfaces of the carrier granules, and dehydrating the mixture thus produced by mixing it with a sterile desiccant in granule form.  It is preferred that the carrier granules be smaller in size, e.g. 50 to 200 mesh, than the desiccant granules, e.g. 5 to 50 mesh, so that, if desired, the carrier granules may be separated from the desiccant granules after the dehydration step.  The preferred carrier is sucrose crystals, which are sterilized at 100 DEG  to 110 DEG  C. for 12 to 24 hours.  Ten grams of the sterile crystals are shaken up in a Petri dish containing the mature spores of a micro-organism grown on a solid agar agar nutrient medium, and the spore-coated crystals so produced are then shaken with 10 grams of sterile desiccant granules in another Petri dish.  Other carriers specified are sugars such as lactose, fructose and dextrose; sodium chloride, magnesium sulphate, sodium nitrate, agar agar granules, gelatine crystals and egg albumen crystals.  Specified dehydrating agents are granules of calcium chloride, mixtures of calcium sulphate and sodium sulphate; and silica gel crystals, preferably containing an indicator which is blue when the crystals are dry and pink when wet.  The spores or cells may be transferred as centrifuged sediment from a liquid medium or from any non-liquid, but moist, solid medium, and the quantities of carrier crystals and desiccant particles are chosen to provide the apparently dry, free-flowing mixture.ALSO:Viable spores or cells of Fungi including the subdivision Schizomycetes are preserved by mixing a moist but not liquid host medium containing the spores or cells, with a sterile water-soluble non-toxic crystalline carrier in granule form so that the spores or cells adhere to the surfaces of the carrier granules, and dehydrating the mixture thus produced by mixing it with a sterile desiccant in granule form.  It is preferred that the carrier granules be smaller in size, e.g. 50 to 200 mesh, than the desiccant granules, e.g. 5 to 50 mesh, so that, if desired, the carrier granules may be separated from the desiccant granules after the dehydration step. The preferred carrier is sucrose crystals, which are sterilized at 100 DEG  to 110 DEG  C. for 12 to 24 hours.  Ten grams of the sterile crystals are shaken up in a Petri dish containing the mature spores of a micro-organism grown on a solid agar agar nutrient medium, and the spore-coated crystals so produced are then shaken with 10 grams of sterile desiccant granules in another Petri dish.  Other carriers specified are sugars such as lactose, fructose and dextrose; sodium chloride, magnesium sulphate, sodium nitrate, agar agar granules, gelatine crystals and egg albumen crystals.  Specified dehydrating agents are granules of calcium chloride, mixtures of calcium sulphate and sodium sulphate; and silica gel crystals, preferably containing an indicator which is blue when the crystals are dry and pink when wet.  The spores or cells may be transferred as centrifuged sediment from a liquid medium or from any non-liquid, but moist, solid medium, and the quantities of carrier crystals and desiccant particles are chosen to provide the apparently dry, free-flowing mixture. Specified are Penicillium notatum, Aspergillus glaucus, Saccharomyces cerevisiae, Streptomyces griseus, Bacillus subtilis, Clostridium Welchii, Escherichia coli, Lactobacillus leichmanii and Micrococcus aureus.